The history of polyamide (PA) resin as an engineering plastic is close to 40 years, yet there still remains a high demand for the same. The continuing demand for polyamide resin is due at least in part to the wide variety of types of polyamide resin, such as PA 6, PA 66, PA 610, PA 612, PA 11, PA 12, PA6T, PA6I, PA9T, and the like, and copolymers or blends thereof, each of which has useful properties and various performance characteristics.
The mechanical properties and heat resistance of polyamide resin can be improved by adding inorganic reinforcing material such as glass fiber. Reinforced polyamide resin compositions can be used in applications such as structural materials and interior and exterior parts of automobiles.
Recently, new light source such as light emitting diodes (LEDs) and electro luminescence (EL) devices is increased as lighting, display and the like since it has low power consumption, long period of life and the like.
Particularly, high heat resistant modified polyamide based resin reinforced by glass fiber and having aromatic rings in the main chain of the modified polyamide based resin, i.e. polyphthalamide (PPA) based resin has been mostly used as a material for the production of various LED components having excellent energy efficiency and energy lifespan, such as reflectors, reflector cups, scramblers, housings and the like. Because the resin can withstand high temperatures used in the production of LED, also exhibit excellent light reflectance with a high whiteness index, minimal deterioration of whiteness resulting from yellowing and can further block the flow of electricity.
Due to environmental regulation, lead-free solders, such as solders made of tin-silver alloy, are increasingly important. Lead-free solders generally have a higher melting point (around 260° C.) than conventional lead-containing solders. Examples of materials applicable in the lead-free solders are limited to liquid crystal polymer (LCP), polyphenylene sulfide (PPS) and polyphthalamide (PPA).
LEDs generally include a semiconductor emitting a light, a lead wire, a reflector as housing, and a transparent sealing product. The reflector can be made of various materials such as ceramic or heat resistant plastics. Ceramics, however, can have problems with productivity, and heat resistant plastics can have reduced optical light reflectance resulting from changes in color that can occur during injection molding process, curing process of sealing product or actually using in the field.
To use polyamide based resin as a material of electronic components such as LEDs, semiconductors and the like, physical properties such as heat resistance, impact strength and the like should not be deteriorated, and thin-wall moldability, light reflectance, yellowing resistance should be improved.